Telephone systems have long been used for voice communication, and more recently for data communication, using such terminal devices as modems and facsimile systems. Typically, voice and data devices are used in a single location with dedicated telephone lines allocated to each type of device. In situations where multiple telephone lines are not available or are economically unfeasible, the telephone line may be coupled in parallel between the telephone set and the terminal device. When a telephone set and a terminal device are coupled in parallel to a single telephone line, a ringing signal cannot be differentiated as a request for voice communication with a telephone set or for data communication with a terminal device. This problem may be avoided with a device which can route an incoming ringing signal to the appropriate device.
Some prior systems, such as those disclosed in U.S. Pat. Nos. 4,660,218 and 4,584,434, show systems which automatically route telephone signals between a telephone set and a terminal device. A major disadvantage of these systems is that they must be connected in series between the telephone lines and the associated telephone set or terminal devices. This type of configuration is typically difficult to install and may require special expertise to implement.
In another type of system disclosed in U.S. Pat. No. 4,444,999, the device automatically disconnects a terminal device when an associated telephone set is taken off-hook. However, this system is not capable of automatically connecting a terminal device.
From the foregoing, no device is known which provides ease of installation while providing a means for automatically routing an incoming message to the appropriate voice or data device as instructed by the sending or receiving party.